Introduction to the X Window System

In many ways, it's easier to explain how the X Window System is different from the interface that you're accustomed to than it is to explain how it's similar. Whether you're from a Mac or a PC background, you're certainly used to a graphical user interface, and both the X Window System and the interface to which you're accustomed display windows with program content and information in them. But beyond this, the X Window System is fundamentally a different interface than the GUI present on either of the popular desktop operating systems.

At the most obvious level, the X Window System is not a built-in part of the operating system. Whereas the Mac OS and Windows graphical user interfaces are intimately tied to the underlying operating system, the X Window System is a completely separate system with no real attachment to the operating system underneath it. This separation makes for inefficiencies in the way the window system interacts with the operating system and is the cause of certain performance issues that are of some annoyance. As you'll see, however, this separation between display and operating system also provides a level of flexibility that cannot be readily accomplished with integrated systems.